In an electrophotographic photosensitive member containing an organic photoconductive material, a contact member (e.g., cleaning blade) is brought into contact with the surface of the electrophotographic photosensitive member. Consequently, it is required to reduce occurrence of image degradation due to the contact stress between the electrophotographic photosensitive member and the contact member, and it is also required to effectively reduce the friction force of the surface of the electrophotographic photosensitive member. Recently, in order to improve the durability of an electrophotographic photosensitive member, a resin having a high abrasion resistance is used as a thermoplastic resin contained in the surface layer of the electrophotographic photosensitive member. As a result, though the surface of the electrophotographic photosensitive member is hardly worn, discharge products generated by the charging process are hardly removed and thereby accumulate on the photosensitive member surface. The discharge products increase the friction force of the photosensitive member surface and also absorb moisture in the air under high humidity to reduce the surface resistance of the electrophotographic photosensitive member. This may cause image deletion.
As a method of reducing the friction force of an electrophotographic photosensitive member, particles or fillers having high lubricity are added to the surface layer of the electrophotographic photosensitive member. PTL 1 proposes a method of reducing the friction force between a photosensitive member and a contact member by adding fluorine resin particles to the surface layer. Alternatively, friction force can be reduced by using particles coated with a material having high lubricity. PTL 2 proposes a method of reducing the friction force between a photosensitive member and a contact member by adding silica particles having surfaces treated with a compound having a siloxane structure to the surface layer of an electrophotographic photosensitive member.
The abrasion resistance of an electrophotographic photosensitive member is also improved by adding acicular fillers of an inorganic material (hereinafter referred to as acicular inorganic fillers) to the surface layer of the electrophotographic photosensitive member. PTL 3 proposes a method of improving the abrasion resistance of a photosensitive member by adding acicular inorganic fillers of potassium titanate to the surface layer.